Construct a Global Data Grid

Imagine an extremely coarse map of the world in which each cell represents 60°. Such a map matrix would be 3-by-6.

1. Create a 3-by-6 grid:

   miniZ = [1 2 3 4 5 6; 7 8 9 10 11 12; 13 14 15 16 17 18];
   

2. Now make a referencing object:

   miniR = georasterref('RasterSize', size(miniZ), ...
      'Latlim', [-90 90], 'Lonlim', [-180 180])
   

   Your output appears like this:

   miniR = 
   
     GeographicCellsReference with properties:
   
                LatitudeLimits: [-90 90]
               LongitudeLimits: [-180 180]
                    RasterSize: [3 6]
          RasterInterpretation: 'cells'
              ColumnsStartFrom: 'south'
                 RowsStartFrom: 'west'
          CellExtentInLatitude: 60
         CellExtentInLongitude: 60
        RasterExtentInLatitude: 180
       RasterExtentInLongitude: 360
              XIntrinsicLimits: [0.5 6.5]
              YIntrinsicLimits: [0.5 3.5]
          CoordinateSystemType: 'geographic'
                     AngleUnit: 'degree'

3. Set up an equidistant cylindrical map projection:

   figure('Color','white')
   ax = axesm('MapProjection', 'eqdcylin');
   axis off
   setm(ax,'GLineStyle','-', 'Grid','on','Frame','on')
   

4. Draw a graticule with parallel and meridian labels at 60° intervals:

   setm(ax, 'MlabelLocation', 60, 'PlabelLocation',[-30 30],...
       'MLabelParallel','north', 'MeridianLabel','on',...
       'ParallelLabel','on','MlineLocation',60,...
       'PlineLocation',[-30 30])
   

5. Map the data using geoshow and display with a color ramp and legend:

   geoshow(miniZ, miniR, 'DisplayType', 'texturemap');
   colormap('autumn')
   colorbar
   

   

Note that the first row of the matrix is displayed at the bottom of the map, while the last row is displayed at the top.